Researchers in the United States have reported that a species of sardine from the waters near Japan has been found off the west coast of the US. They say the warmed seawater could have helped the fish cross the Pacific Ocean.

The US National Oceanic and Atmospheric Administration, or NOAA, has released the results of its genomic analysis of sardines caught on the West Coast in 2022 and 2023.

The researchers found that the samples collected during those years were a mixture of Pacific sardines, a species common on the west coast of the US, and Japanese sardines, which were known to live only in the western part of the North Pacific Ocean, near Asia from East, including Japan. .

The researchers say analyzes of sardines collected from 2013 to 2021 off the US West Coast found no sign of Japanese sardines, suggesting their journey across the ocean is a more recent development.

Researcher Gary Longo noted that the temperature in the North Pacific has increased. He said he believes the Japanese sardines made their way across the Pacific after spending some time in the southern Bering Sea and waters near the Aleutian Islands.

He suspects that their long journey was possible after the waters became warm enough for them to live in the winter.